#include "types.h"
#include "defs.h"
#include "param.h"
#include "memlayout.h"
#include "mmu.h"
#include "x86.h"
#include "proc.h"
#include "spinlock.h"

#ifndef SCHEDFLAG
	#define SCHEDFLAG 0
#endif

//FF 	0
//FRR 1
//GRT 2
//3Q 	3

//Policies
#define _RR			0	
#define _FRR		1	
#define _GRT		2	
#define _3Q			3

//Priorities		
#define HIGH		0	
#define MEDIUM	   1	
#define LOW			2	
	


struct {
  struct spinlock lock;
  struct proc proc[NPROC];
} ptable;



static struct proc *initproc;

int nextpid = 1;
extern void forkret(void);
extern void trapret(void);
struct proc* mediumQueue[NPROC];
struct proc* aux[NPROC];
struct proc* ans;
struct proc* deqprocs;
int head = 0;
int tail = 0;
int curr = 0;


static void wakeup1(void *chan);



int anyAlive(int flag)
{
	struct proc* p;
	int deqprocs = 0;
	for (p=ptable.proc ; p < &ptable.proc[NPROC] ; p++)
		{
			if ((p->state == RUNNABLE || p->state == RUNNING) && p->priority == flag)   
				return 1;
		}
	return deqprocs;	
}




double getRatio (double time,struct proc* a)
{
	double lifetime = (double)time - (double)a->ctime;
	if (lifetime == 0)
	 return -1;															//if process is a "chong" it must wait!!!
	return ((double)(a->rtime)/ lifetime);	
}



struct proc* getMinRatio(struct proc* p) 
{
   int first = 0;
   acquire (&tickslock);
	int time = ticks;
	release (&tickslock);

  
  for (p=ptable.proc ; p < &ptable.proc[NPROC] && p->priority == HIGH ; p++)
	{
		//cprintf("first = %d\n", first);
		if(p->state != RUNNABLE) 
			continue;
		
		if (first == 0)
		{
			ans = p;
			first = 1;
		}
		//(double)getRatio((double)time,ans)>=(double)getRatio((double)time,p)
		else if (getRatio(time,p) != -1   &&   getRatio(time,p) <= getRatio(time,ans))
			ans = p;	
	}
	return ans;
}

void enqueue(struct proc* p) 
{
	
	mediumQueue[tail] = p;
	tail = (tail+1) % NPROC;
}



struct proc* dequeue() 
{
  deqprocs = mediumQueue[head];
  head = (head+1) % NPROC;
  return deqprocs;
}

void
pinit(void)
{
  initlock(&ptable.lock, "ptable");
}

//PAGEBREAK: 32
// Look in the process table for an UNUSED proc.
// If found, change state to EMBRYO and initialize
// state required to run in the kernel.
// Otherwise return 0.
static struct proc* allocproc(void)
{
  struct proc *p;
  char *sp;

  acquire(&ptable.lock);
  for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
    if(p->state == UNUSED)
      goto found;
  release(&ptable.lock);
  return 0;

found:
  p->state = EMBRYO;
  p->pid = nextpid++;
  release(&ptable.lock);

  // Allocate kernel stack.
  if((p->kstack = kalloc()) == 0){
    p->state = UNUSED;
    return 0;
  }
  sp = p->kstack + KSTACKSIZE;
  
  // Leave room for trap frame.
  sp -= sizeof *p->tf;
  p->tf = (struct trapframe*)sp;
  
  // Set up new context to start executing at forkret,
  // which returns to trapret.
  sp -= 4;
  *(uint*)sp = (uint)trapret;

  sp -= sizeof *p->context;
  p->context = (struct context*)sp;
  memset(p->context, 0, sizeof *p->context);
  p->context->eip = (uint)forkret;
  //ours
  acquire(&tickslock);
  p->ctime = ticks;
  p->priority=HIGH;
  p->rtime = 0;
  release(&tickslock);
  return p;
}


//PAGEBREAK: 32
// Set up first user process.
void
userinit(void)
{
  struct proc *p;
  extern char _binary_initcode_start[], _binary_initcode_size[];
  
  p = allocproc();
  initproc = p;
  if((p->pgdir = setupkvm(kalloc)) == 0)
    panic("userinit: out of memory?");
  inituvm(p->pgdir, _binary_initcode_start, (int)_binary_initcode_size);
  p->sz = PGSIZE;
  memset(p->tf, 0, sizeof(*p->tf));
  p->tf->cs = (SEG_UCODE << 3) | DPL_USER;
  p->tf->ds = (SEG_UDATA << 3) | DPL_USER;
  p->tf->es = p->tf->ds;
  p->tf->ss = p->tf->ds;
  p->tf->eflags = FL_IF;
  p->tf->esp = PGSIZE;
  p->tf->eip = 0;  // beginning of initcode.S

  safestrcpy(p->name, "initcode", sizeof(p->name));
  p->cwd = namei("/");

  p->state = RUNNABLE;
  p->priority = HIGH;
  if (SCHEDFLAG == _FRR && p!=0)
    enqueue(p);

}

// Grow current process's memory by n bytes.
// Return 0 on success, -1 on failure.
int
growproc(int n)
{
  uint sz;
  
  sz = proc->sz;
  if(n > 0){
    if((sz = allocuvm(proc->pgdir, sz, sz + n)) == 0)
      return -1;
  } else if(n < 0){
    if((sz = deallocuvm(proc->pgdir, sz, sz + n)) == 0)
      return -1;
  }
  proc->sz = sz;
  switchuvm(proc);
  return 0;
}

// Create a new process copying p as the parent.
// Sets up stack to return as if from system call.
// Caller must set state of returned proc to RUNNABLE.
int
fork(void)
{
  int i, pid;
  struct proc *np;

  // Allocate process.
  if((np = allocproc()) == 0)
    return -1;

  // Copy process state from p.
  if((np->pgdir = copyuvm(proc->pgdir, proc->sz)) == 0){
    kfree(np->kstack);
    np->kstack = 0;
    np->state = UNUSED;
    return -1;
  }
  np->sz = proc->sz;
  np->parent = proc;
  *np->tf = *proc->tf;

  // Clear %eax so that fork returns 0 in the child.
  np->tf->eax = 0;

  for(i = 0; i < NOFILE; i++)
    if(proc->ofile[i])
      np->ofile[i] = filedup(proc->ofile[i]);
  np->cwd = idup(proc->cwd);
 
  pid = np->pid;
  np->state = RUNNABLE;
  np->priority = HIGH;
  if(SCHEDFLAG == _FRR && np!=0)
    enqueue(np);
  safestrcpy(np->name, proc->name, sizeof(proc->name));
  return pid;
}

// Exit the current process.  Does not return.
// An exited process remains in the zombie state
// until its parent calls wait() to find out it exited.
void
exit(void)
{
  struct proc *p;
  int fd;

  if(proc == initproc)
    panic("init exiting");

  // Close all open files.
  for(fd = 0; fd < NOFILE; fd++){
    if(proc->ofile[fd]){
      fileclose(proc->ofile[fd]);
      proc->ofile[fd] = 0;
    }
  }

  iput(proc->cwd);
  proc->cwd = 0;
  acquire(&ptable.lock);
//ours
	
acquire(&tickslock);
  proc->etime = ticks;
release(&tickslock);
  // Parent might be sleeping in wait().
  wakeup1(proc->parent);

  // Pass abandoned children to init.
  for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
    if(p->parent == proc){
      p->parent = initproc;
      if(p->state == ZOMBIE)
        wakeup1(initproc);
    }
  }

  // Jump into the scheduler, never to return.
  proc->state = ZOMBIE;
  sched();
  panic("zombie exit");
}

// Wait for a child process to exit and return its pid.
// Return -1 if this process has no children.
int
wait(void)
{
  struct proc *p;
  int havekids, pid;

  acquire(&ptable.lock);
  for(;;){
    // Scan through table looking for zombie children.
    havekids = 0;
    for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
      if(p->parent != proc)
        continue;
      havekids = 1;
      if(p->state == ZOMBIE){
        // Found one.
        pid = p->pid;
        kfree(p->kstack);
        p->kstack = 0;
        freevm(p->pgdir);
        p->state = UNUSED;
        p->pid = 0;
        p->parent = 0;
        p->name[0] = 0;
        p->killed = 0;
        release(&ptable.lock);
        return pid;
      }
    }

    // No point waiting if we don't have any children.
    if(!havekids || proc->killed){
      release(&ptable.lock);
      return -1;
    }

    // Wait for children to exit.  (See wakeup1 call in proc_exit.)
    sleep(proc, &ptable.lock);  //DOC: wait-sleep
  }
}

int wait2(int* wtime, int* rtime)
{
  struct proc *p;
  int havekids, pid;

  acquire(&ptable.lock);
  for(;;){
    // Scan through table looking for zombie children.
    havekids = 0;
    for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
      if(p->parent != proc)
        continue;
      havekids = 1;
      if(p->state == ZOMBIE){
        // Found one.
			*rtime = p->rtime;
			*wtime = p->etime - p->ctime - p->rtime;
        pid = p->pid;
        kfree(p->kstack);
        p->kstack = 0;
        freevm(p->pgdir);
        p->state = UNUSED;
        p->pid = 0;
        p->parent = 0;
        p->name[0] = 0;
        p->killed = 0;
        release(&ptable.lock);
        return pid;
      }
    }

    // No point waiting if we don't have any children.
    if(!havekids || proc->killed){
      release(&ptable.lock);
      return -1;
    }

    // Wait for children to exit.  (See wakeup1 call in proc_exit.)
    sleep(proc, &ptable.lock);  //DOC: wait-sleep
  }
}

int nice()
{

  int found = 0;
  int i;
  cprintf("entering nice\n\n");
  if (SCHEDFLAG != _3Q || proc->priority == LOW || proc==0)
    return -1;
  else    
  {  
    proc->priority++;
    if (proc->priority == MEDIUM)
      enqueue(proc);
    else 
    {
      for (i=head; (i%NPROC) != tail && !found ; i++)
      {
        if (mediumQueue[i%NPROC] == proc)
          {
            found=1;
            break;
          } 
      }
      for ( ;(i%NPROC) != tail ; i++ )
            mediumQueue[i%NPROC] =  mediumQueue[(i+1)%NPROC];
      if (tail==0)
         tail = NPROC-1;
      else
         tail = (tail-1) % NPROC;
      }   

  }  
return 0;       
}


void
register_handler(sighandler_t sighandler)
{
  char* addr = uva2ka(proc->pgdir, (char*)proc->tf->esp);
  if ((proc->tf->esp & 0xFFF) == 0)
    panic("esp_offset == 0");

    /* open a new frame */
  *(int*)(addr + ((proc->tf->esp - 4) & 0xFFF))
          = proc->tf->eip;
  proc->tf->esp -= 4;

    /* update eip */
  proc->tf->eip = (uint)sighandler;
}


//PAGEBREAK: 42
// Per-CPU process scheduler.
// Each CPU calls scheduler() after setting itself up.
// Scheduler never returns.  It loops, doing:
//  - choose a process to run
//  - swtch to start running that process
//  - eventually that process transfers control
//      via swtch back to the scheduler.
void scheduler(void)
{
  struct proc* p;

	for(;;){
	    // Enable interrupts on this processor.
		sti();
		acquire(&ptable.lock);
		if (SCHEDFLAG == _FRR)
		{
			if (head!=tail)
			{
				p = dequeue();
				proc = p;
				switchuvm(p);
				p->state = RUNNING;
				swtch(&cpu->scheduler, proc->context);
				switchkvm();

				// Process is done running for now.
				// It should have changed its p->state before coming back.
				proc = 0;
			}
		}
		else if (SCHEDFLAG == _GRT)
		{
			p=getMinRatio(p);
			proc = p; 
			switchuvm(p);
			p->state = RUNNING;
			swtch(&cpu->scheduler, proc->context);
			switchkvm();

			// Process is done running for now.
			// It should have changed its p->state before coming back.
			proc = 0;
		}
		else if (SCHEDFLAG == _3Q)
		{
			if (anyAlive(HIGH) == 1)
			{
				p=getMinRatio(p);

        proc = p; 
        switchuvm(p);
        p->state = RUNNING;
        swtch(&cpu->scheduler, proc->context);
        switchkvm();
			}			
			else if(anyAlive(MEDIUM) == 1)
			{
				p = dequeue();

				proc = p; 
				switchuvm(p);
				p->state = RUNNING;
				swtch(&cpu->scheduler, proc->context);
				switchkvm();
			}
			else
			{
				for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
				{
					if(p->state != RUNNABLE)
			  			continue;

			  	proc = p; 
					switchuvm(p);
					p->state = RUNNING;
					swtch(&cpu->scheduler, proc->context);
					switchkvm();
					proc = 0;	
			  	}	
			}
		}
		else
		{
			// Loop over process table looking for process to run.

			for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
			{
				if(p->state != RUNNABLE)
			  		continue;

			// Switch to chosen process.  It is the process's job
			// to release ptable.lock and then reacquire it
			// before jumping back to us.

			proc = p;
			switchuvm(p);
			p->state = RUNNING;
			swtch(&cpu->scheduler, proc->context);
			switchkvm();

			// Process is done running for now.
			// It should have changed its p->state before coming back.
			proc = 0;
			}
		}		
		release(&ptable.lock); 
	}
}

// Enter scheduler.  Must hold only ptable.lock
// and have changed proc->state.
void sched(void)
{
  int intena;

  if(!holding(&ptable.lock))
    panic("sched ptable.lock");
  if(cpu->ncli != 1)
    panic("sched locks");
  if(proc->state == RUNNING)
    panic("sched running");
  if(readeflags()&FL_IF)
    panic("sched interruptible");
  intena = cpu->intena;
  swtch(&proc->context, cpu->scheduler);
  cpu->intena = intena;
}

// Give up the CPU for one scheduling round.
void yield(void) 
{
  acquire(&ptable.lock);  //DOC: yieldlock
  proc->state = RUNNABLE;
	if (SCHEDFLAG == _3Q)
	{
		if (proc->priority == MEDIUM && proc!=0)
			enqueue(proc);
	}
	else if (proc!=0 && SCHEDFLAG == _FRR)
		enqueue(proc);
  sched();
  release(&ptable.lock);
}

// A fork child's very first scheduling by scheduler()
// will swtch here.  "Return" to user space.
void
forkret(void)
{
  static int first = 1;
  // Still holding ptable.lock from scheduler.
  release(&ptable.lock);

  if (first) {
    // Some initialization functions must be run in the context
    // of a regular process (e.g., they call sleep), and thus cannot 
    // be run from main().
    first = 0;
    initlog();
  }
  
  // Return to "caller", actually trapret (see allocproc).
}

// Atomically release lock and sleep on chan.
// Reacquires lock when awakened.
void
sleep(void *chan, struct spinlock *lk)
{
  if(proc == 0)
    panic("sleep");

  if(lk == 0)
    panic("sleep without lk");

  // Must acquire ptable.lock in order to
  // change p->state and then call sched.
  // Once we hold ptable.lock, we can be
  // guaranteed that we won't miss any wakeup
  // (wakeup runs with ptable.lock locked),
  // so it's okay to release lk.
  if(lk != &ptable.lock){  //DOC: sleeplock0
    acquire(&ptable.lock);  //DOC: sleeplock1
    release(lk);
  }

  // Go to sleep.
  proc->chan = chan;
  proc->state = SLEEPING;
  sched();

  // Tidy up.
  proc->chan = 0;

  // Reacquire original lock.
  if(lk != &ptable.lock){  //DOC: sleeplock2
    release(&ptable.lock);
    acquire(lk);
  }
}

//PAGEBREAK!
// Wake up all processes sleeping on chan.
// The ptable lock must be held.
static void
wakeup1(void *chan)
{
  struct proc *p;
  for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
  {  
      if(p->state == SLEEPING && p->chan == chan)
      {
         p->state = RUNNABLE;
         if (SCHEDFLAG == _3Q)
         {
            if (p->priority == MEDIUM && p!=0)
               enqueue(p);
         }
         else if (p!=0 && SCHEDFLAG == _FRR)
            enqueue(p); 
      }  
  }
}  

// Wake up all processes sleeping on chan.
void
wakeup(void *chan)
{
  acquire(&ptable.lock);
  wakeup1(chan);
  release(&ptable.lock);
}

// Kill the process with the given pid.
// Process won't exit until it returns
// to user space (see trap in trap.c).
int
kill(int pid)
{
  struct proc *p;

  acquire(&ptable.lock);
  for(p = ptable.proc; p < &ptable.proc[NPROC]; p++)
  {
    if(p->pid == pid)
    {
      p->killed = 1;
      // Wake process from sleep if necessary.
      if(p->state == SLEEPING)
      {
        p->state = RUNNABLE;
	     if (SCHEDFLAG == _3Q)
        {
          if (p->priority == MEDIUM && p!=0)
            enqueue(p);
        }
        else if (p!=0 && SCHEDFLAG == _FRR)
          enqueue(p);  
        release(&ptable.lock);
        return 0;
      }  
    }
  }  
  release(&ptable.lock);
  return -1;
}

//PAGEBREAK: 36
// Print a process listing to console.  For debugging.
// Runs when user types ^P on console.
// No lock to avoid wedging a stuck machine further.
void
procdump(void)
{
  static char *states[] = {
  [UNUSED]    "unused",
  [EMBRYO]    "embryo",
  [SLEEPING]  "sleep ",
  [RUNNABLE]  "runble",
  [RUNNING]   "run   ",
  [ZOMBIE]    "zombie"
  };
  int i;
  struct proc *p;
  char *state;
  uint pc[10];
  
  for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){
    if(p->state == UNUSED)
      continue;
    if(p->state >= 0 && p->state < NELEM(states) && states[p->state])
      state = states[p->state];
    else
      state = "???";
    cprintf("%d %s %s", p->pid, state, p->name);
    if(p->state == SLEEPING){
      getcallerpcs((uint*)p->context->ebp+2, pc);
      for(i=0; i<10 && pc[i] != 0; i++)
        cprintf(" %p", pc[i]);
    }
    cprintf("\n");
  }
}


